Underreamer



Sept. 2, 924. 1,507,039

w. 5. your;

UNDERREAMER Filed Aug. 9, 1921 5 Sheets-Sheet 1 Patented Sept. 2, 1924.

WILLIAM E. YOULE, OF ANGELES, CALIFORNIA.

UNDERREAMER.

Application filed August 9, 1921.

To all whom it may concern:

Be it known that 1, WILLIAM E. YOULE, a citizen of the United States, residing at Los .Angeles, in the county of Los Angeles and Fvtate of Cali toi'nia, have invented a new and useful Underreamer, of which the following is a specification.

This invention relates to underreamers of the impact type particularly adapted for use with the cable system of well drilling, the main objects of the invention being to provide an underreamer which is far superior to any in the prior art, by reason of its great strength, especially in the shanks of the cutters, the ease with which the cut ters can be removed from the body without disconnecting the cutter operating spring, and especially by reason of certain provisions and featuresof construction by which the spring bolt if broken will still be re tained against loss and enabling the cutters to be retained within the body even though the spring bolt be broken.

Another object of major importance resides in the expanding operation of the cut ters which are translated from collapsed to expanded positions in stepped movements first unlatching and expanding the cutters to a point slightly less than full expanded position, translating the cutters vertically upward and subsequently completing the expanding movement, whereby a slight collapsing relief of the cutters is provided to release the cutters, when wedged in a well bore, without effecting a latching of the cutters.

Another object is to provide an underreamer in which the supporting engagement of the cutters upon the spring bolt. is below the shanks of the cutters, whereby the shanks are devoid of weakening apertures or recesses. r v

A further object resides in the provision of a one-piece body having side opening spring chamber with a spring retaining nut on the spring rod, which is retained against turning by engagement with the walls of the recess whereby the tension of the spring can be regulated by a. turning of the spring rod.

Another object is to provide an underreamer in which the spring rod has a supporting engagement with the body portion of the cutters whereby I am permitted to provide solid imperforate cutter shanks and in which the cutters have inthrust bean Serial No. 491,017.

ing projections which overlap each other when the cutters are in collapsed position, this overlapping structure permitting the cutters to be constructed so that they will come closely together when collapsed, so that they can be expanded to a maximum degree and when expanded will leave a maximum open space therebetween to receive the drilling refuse, and so as to have a great width of cutter shank in the direction of cutter expansion.

Another object is to provide an underreamer from which the cutters may be removed without disturbing the spring and spring rod.

Other objects reside in the provision of maximum upthrust bearing surfaces, outthrust bearing surfaces, and inthrust bearing surfaces on the body and on the cooperating cutters, the provision of means preventing the cutters dropping fromv the body when the supporting spring bolt breaks, and in the provision of means whereby abroken spring rod is retained by the cutters against dropping from the body.

Various other objects and advantages will be more fully apparent from the following description of the accompanying drawings which form a part of this disclosure, and which illustrate a preferred embodiment of the invention.

Of the drawings Figure 1 is a side elevation of my improved underreamer, with the cutters in expanded position.

Fig. 2 is a similar elevation of the lower portion of the underreamer, with the cutters in collapsed position.

Fig. 3 is an enlarged plan section on line of Fig. 1.

Fig. 4: is a plan section on line ra -a," of Fig. 5. y

5 is a vertical section showing the cutters in closed position.

Fig. 6 is a plan section on line 00 -02 of Fig. 5.

Fig.

7 7 is a section similar to Fig. 5, showing the cutters in relief position andprior to their final movement of expansion.

Fig. 8 is a plan section on line m'm of Fig. 7 l Fig. 9 is a section similar to Fig. 7 showingthe cutter-sin fully expanded position.

Fig. 10 is a detail vertical section through the lower portion of the reamer body.

Fig. 11 is a side elevation partly in section,;of the reamer body, looking from the right side of Fig. 10.

Fig. 12 is a bottom plan view partly in section, of Fig. 9,

Fig. 13 is a vertical section illustrating the method of removing the cutters from the bod t Fig. 14 is a detail bottom plan view ofthe. reamer body.

Fig. 15 is a perspective view of the lower portion of the reamer body.

.w-ill be retained in the tool.

Fig. 16 is an elevation of the lower portion of the underreamer looking from the right side of Fig. 1.

Fig. 17 is a detail perspective view of thelower end of the spring bolt. Figs. 18 and 19 are detail. perspective views of the cutters.

F 20 is a diagram of the cutter movements of the ordinary types of underreamer, and

Fig. 21 is a similar diagram of the cutter movements of the underreamer oi the pres ent invention. I

lVhen reaming in solt sticky lOTIlldtlOll with reamers of the general type herein reterred to and also when reaming in hard rock the cutters sometimes become stuck in the well bore; with the ordinary forms of underreamers now in use the cutters are released from such stuckor wedged condition by elevating the reamer body until the cutters are fully collapsed and latched beneath their expanding shoulders.

In some formations the cutters stick at every stroke and the repeatedlatching under the heavy snapping tension of the spring causes crystallization and breaking ot the Further in the usual types of underrreanr ers in which the cutters are supported by a spring rod, the rods head usually engages into recesses or slots in the cutter shanks andin such cases the recesses or slots so weaken the shanks that under severe usage they break off and the cutters drop from the reainer body. In my improved tool the head of the spring rod engages into pockets in the main'body portion of the cutters, and the rod and said pockets are so formed that if the rod becomes broken it This structure permits me to form thecutter shanks without any weakening slots or recesses and of great size and strength compared with those now in general use.

By providing a means independent of the spring rod, for retaining the cutters against dropping from the body I elfectively prevent a loss of one or both cutters even though the spring rod should become broken and lost in the well hole.

Referring now to the drawings a detailed description of the preferred form illustrated willbe' given with like parts throughout the several views correspondingly numbered.

The tmderreamer body.

With particular reference to Figures 1, 10, 11, 14, 15, and 16 I will first describe the formation of the'body 1 of the underreamer which is of cylindrical form with its upper portion provided with a squared shank 2 and a tapered threaded pin 3 adapting it-to be joined to other elements of a tool string.

The medial portion of the body has a side opening recess providing a spring chamber 4 and the lower portion of the body has] diametrically opposed slots 5-5extending upwardly from the lower surface of the body and inwardly to a central web 6 providing inthrust bearingsurfaces 77 for engagement by the shanks of the cutters, the opposed side walls of each slot being grooved to provide slideways 7 for the cutters and define outthrust bearing surfaces 8.

The web 6 extends upwardly to approxi-- mately the same height as the slots 5 and above said web the slots merge together to form a chamber 9 of a width coinciding with the base of the grooves in the side The web 6 terminates walls of the slots. short of the lower end of the body, with its lower surface inclined from the center of the body outwardly and upwardly to provide cutter latching and expanding shoulders 10-10 and the body is provided with Vshaped projections ill-11 extending downwardly onopposite sides of the slots 5', said project-ions defining the inner limits of the upthrust bearing surfaces 1212 of the body and providing opposed inthrust supporting or bearing surfaces l313. means for rigidly resisting or supporting the inthrust o1 the'cutters when they are in operation' The opposite walls of the chamber 9 have rectangular orifices or slots letransversely alined with thelr outer faces or walls flush with the wall otthe chamber and their lower walls approximately alined with the top walls of the slots 5. (See Figs. 10, 11, 15.) Circularly spaced from one of the slotslt I provide recesses 15-16 with the intermediate walls having a transverse bore 17 alined in-aplane intersecting the center of the ori- .tice. The openings 14L are adapted to re- These faces are the preferred ceive removable retaining key 18 which extends across the chamber 9 and is retained in place by a split cotter pin 19 inserted through the bore 17 and through a hole in said key with the ends of the pin spread apart to retain it in place. (See Figs. 4 and 16). The function of this retaining key will be fully explained later.

It will be evident that to properly machine the chamber 9 would be difficult if not impossible, therefore, it will be stated that my preferable method of forming the cha1nber consists of cutting directly through the body the full height and width of said chamber and after the body is properly machined the walls 20 are formed of separate pieces of the contour indicated by heavy dotted lines in Fig. 11, and subsequently welded or brazed in place.

I provide spring actuated means for pulling the cutters upwardly in the body. For this purpose the Walls separating the chamber 9 and the spring chamber 4, and the web 6 of the body have centrally disposed vertically alined bores 21-22 to accommodate a spring rod 23 having an approximately square head 24 at its lower end. (See Fig. 17). Said head is positioned below the Web 6 of the body with the rod extending upwardly into the spring chamber 4 and the upper end of the rod is screw threaded into a square nut 25. An actuating spring26 surrounds the rod between the lower Wall of the spring chamber and the nut 25; the spring chamber is preferably of slot form adjacent the nut so that the sides of the nut will engage the side walls of the sprin chamber to prevent a turning of the nut; ence by a rotation of the spring rod 23 the tension of the spring 26 can be varied as desired (seeFigs. 3 and 16). The head 24 provides opposed cutter supporting table surfaces 27 and the head is strengthened by fillets 28. (See Fig. 17).

T he cutters.

The cutters and the body are provided with means whereby a relative upward and downward movement of the-body collapses and expands the cutters. The cutters are of duplicate construction, (see particularly Figs. 18 and 19), each having a body portion 30 and a shank 31, the upper surface of in collapsed position the opposed projections 33 and recesses will intermesh. A pocket 36 is formed in the inner surface of the cutter body 30 to receive the head 24 of the spring rod 23, said pocket defining ledges 37,37 adapted to rest upon the supporting table surfaces 27, 27 of the bolt head 24, and a lower wall or face 38 which serves as a means for preventing the bolt dropping from the tool. The lower portion of the inner face of the cutter shank 31 has a boss with an inclined upper end operating as a cutter expanding cam 40, and with ad jacent guide surfaces 414l, the boss and the cutter body being centrally grooved to provide clearance for the spring rod and head fillets 28.

The cutter shank 31 has the usual carn shoulder 42 on its outer side and the opposite sides of the shank have projecting guide ribs 43 for guiding the shank in the slideways 7 of the tool body 1. Said ribs define cutter outthrust bearing surfaces 44 and are cut away as at 44 to facilitate removal of the cutter from the tool body as will later be described.

The upper ends of the cuttershanks are =transversely grooved on opposite sides as at 45, the height or length of each groove being slightly greater than the full vertical movements of the cutters plus the height of the cutter retaining key 18 previously described. The upper ends of the grooves 45 define elevated stop shoulders 46 and when the cutters are assembled in the tool body the retaining key 18 which passes through one of the grooves 45 of each cutter with the stop shoulders 46 above the key so in case the cutter supporting spring rod becomes brokenthe cutters will be retained in the tool by the key 18. )Vhile only one of the grooves 45 of each cutter shank engages over the key 18, the shank is provided with such a groove on each side of the shank so as to provide a universal type of cutter instead of separate right and left hand out ters. The upper ends of the cutter shanks taper upwardly to allow for the various rocking movements of the cutters during their expanding and collapsing operations and also during their insertion into and removal from the tool body.

A screw threaded hole is provided in the head of the spring rod to receive an eye bolt 47 see Fig. 13) which is utilized during the insertion or removal of the cutters.

Assembling and disms'sevnbling 0/ cutters.

Assuming that the spring and spring rod is properly assembled in the body and that the rod is drawn down by suitable means attached to the eye bolt 47 (see Fig. 13), each cutter will be inserted into the body in the position of the left hand cutter in said figure this being permitted by the clearance 3 provided by the cutaway portions 44 f the ribs 43. As the pocket 36 of the cutter is now opposite the head 24 of the spring rod the cutter may be swung inward (as'is the right-hand cutter in Fig. 13) the ledges 37 engaging over the companion table surfaces 27 of the bolt head 24 so that wl'ien the bolt is released it will elevate the cutters into the body with the ribs 43 of the cutters s'lidably engaging into the slideways 7 of the body. With the cutters so assembled the retaining key 18 is inserted through the body orifices 14 and secured in place by the cotter pin 19 as previously explained. A. removal of the cutters is effected by a reversal of the above operation.

Operation.

In collapsed condition the cutters assume the position shown in Fig. with the surfaces 50 of the cutters engaging the well casing as the under reamer is lower-ed into the well, to maintain. the cutters collapsed. The cam shoulders 40 are engaged under the expanding shoulderslO of the web 6 of the body and the projections 33 and recesses 35 of the cutters are intermeshed on opposite sides of the head of the spring ro When the underreamer has passed through the casing shoe the cutters are free to be expanded and the spring 26 functions in the usual manner to draw the spring rod 23 upwardly to elevate and expand the cutters.

During the first portion of the upward movement of the cutters the cutter expand- I the cutters their inclined inthrust' bearing surfaces 34 are brought into contact with the intl rustbearing surfaces 13 of the V- shaped projections 11 of the body and duringthe final part of the upward travel of the cutters the cooperation of these inthrust bearing surfaces expand the cutters to their maximum degree, as shown in Figs. 1 and 9. It will, therefore,be understood that the cutters are first unlatched by the co-actingof the latch shoulders 10 and the cam shoulders 40 and expanded nearly to their maximum degree, second, the cutters are drawn vertically upward with their guide surfaces 41' contacting the surface 7 of the body, and finally by the coacting of the inthrust bearing surfaces 13 and 34 of the body and cutters, the cutters aregiven theirfinal degree of expansion in which the latch shoulders 10 and cam shoulders 40 above referred to have no cooperation.

Incollapsing the cutters they follow a reversal of the above-described stepped move ments from expanded to latched positions, the collapsing being accomplished in the usual manner by an engagement of the shoulders 42 with the mouth of the easing shoe which earns the cutters inwardly to latched position while the body 1 is being elevated.

With the cutters in expanded position, and having become stuck 'or wedged tight ly in the well bore, it becomes necessary to at least partially collapse the cuttersto provide suflicient relief to free the out ters. With the ordinary types of underreamers this is accomplished by pulling the reamer body upwardly against the shoe until a full latching of the cutters is effected, but in the present tool, I provide for 'a slight primary collapsing movement independent of the main latching, this primary collapsing of the cutters being initiated or accomplished by the upward move- Inentof the body and its inclined inthrust bearing'surfaces 13 along the cooperating inthrust bearing surfaces 34 of the cutters from the position illustrated in Fig. 9 to that illustrated in Fig. 7. This provides collapsing relief "to the degree indicated at 51 which is suflicient to release the stuck or wedged cutters. By effecting this collapsing relief without completely collapsing and latching the cutters I eliminate to a great degree, the crystallizing effect which a repeated latching under the full tension of the spring producesand for this reason overcome the usual tendency of the moving parts to break under hard usage.

In Figs. 2021 I have illustrated in diagram, the dilferences betweenthe collapsing and expanding movements of the cut t ers of the ordinary types of underreamers and the underreamer of the present invention. In Fig. 20 is indicatedthe movements of the ordinary types of unde'rreamers in which the full expanding of the cutters is performed in one movement '0 and in which to indicates the subsequent vertical movement of the cutter. In Fig. 21 is indicated the movements of the cutters of the underreamer herein, in. which 1? indicates the unlatching and latching movement to efit'e'ct the major portion of the expanding or collapsing of the cutters, 1 indicating the straight vertical travel of the cutters, and 2 indicating the final expanding and the pri mary collapsing movements. The movement in Fig. 20 is a two-step movement with the entire expanding and collapsingconfined to one of the movements, while the movement in Fig. 21 is a three-step move-, ment with the. expanding and collapsing divided and at "opposite ends of the intermediate vertical movement.

From an examination of these diagrams it will be evident that in the ordinary type of tool, the only collapsing relief avail-' able to release stuck or wedged cutters is by a full collapsing and latching of the cutters, while in the tool as herein shown and described a collapsing relief is immediately available independent of the main collapsing and latching of the cutters.

As previously stated, in the event that the spring rod becomes broken it will be retained against loss and also that the cutters themselves will be retained within the tool body. By reference to Fig. 9 it will be noted that with the cutters fully expanded, the space between the outer edges of the lower walls 38 of the pockets 36 in the cutter bodies is less than the width of the head 24: of the spring rod 23, therefore it will be evident that it would be impossible for the rod to drop free from the cutters and as the rod constitutes the supporting means for the cutters it will be plain that should the rod become broken both the cutters and the rod would drop together. Such dropping of the cutters will only continue until the stop shoulders 46 on the upper ends of the cutter shanks strike the top of the retaining key 18 and as such key is rigidly fixed in the tool body it will be understood that the cutters cannot become lost from the body unless the heavy key 18 is broken or the stop shoulders 46 of the cutter shanks become sheared off. One of the advantages of my device is that the key 18 limits the relative upward movement of the body 1, thereby preventing compression of the spring sufliciently to break it.

It will become evident from the above detailed description that my improved underreamer fulfils each and all of the objects primarily stated and While the specific structure illustrated is of a pre ferred embodiment it is to be understood that such modification and changes as fall within the language of the following claims are embraced in the broad scope of the invention.

I claim:

1. An underreamer comprising a body having slideways, cutters slidable therein, and means for translating the cutters, the body and cutters having coo erating surfaces causing an expansion an maintenance of the cutters during their translation, in an "intermediate expanded relation, and thereafter in a completely expanded relation.

2. An underreamer comprising a body having slideways, cutters slidable therein,

and means for translating the cutters, the body and cutters having cooperating surfaces causing an expanslon and maintenance of the cutters in an intermediate expanded relation during the first portion of their translation and having other cooperating surf-aces causing a final. expansion of the cutters during the final portion of their translation.

3. An underreamer comprising a body having slideways, cutters having shanks slidable within said slideways, a spring actuated rod engaging the cutters below their shanks, and means on the body and independent of the rod for limiting the upward and downward movement of the cutters.

4:. An underreamer comprising a bodyhaving slideways, cutters having shanks slidable within said slideways and provided with pockets in their body portions below their shanks defining supporting ledges, and' a spring actuated rod carried by the body and having a head positioned within said pockets and having cutter supportin table surfaces engaging the supporting ledges of the cutters.

5. An underreamer comprising a body having slideways, cutters having shanks provided with ribs slidable within said slide-- ate web having cutter expanding shoulders and with their side walls grooved to provide slideways, the body having angled inthrust bearing surfaces, cutters having shanks slidable in the slots, opposed ribs slidable in the slideways, cam shoulders normally latching under the expanding shoulders, and angled inthrust bearing surfaces; the combination with the above named elements, of a spring actuated rod engaging the cutters and func tioning to translate the cutters to (jause an unlatching and expansion of the cutters by cooperation of the expanding shoulders of the body and the cam shoulders of the out ters, a subsequent vertical translation of the cutters without further expansion, and a final expansion of the cutters by cooperation of the inthrust bearing surfaces of the bod and the cutters.

8. An underreamer comprising a body having opposed slideways and intermediate" projections providing inthrustbearing surfaces, opposed cutters having shanks slidableinlsaid slideways, and a spring actuated cutter translating rod carried by the body and engaging the cutters, the inner opposed surfaces. of the cutter bodies having angled projections providing inthrust bearing. surfaces and adjacent recesses on opposite sides of the rod, the projections of each cutter.

aligning to intermeshwithin the recesses of the opposite cutter.

and having shank-s, with stop shoulders, means for translating the cutters in combination with means removably carried by the a body cooperatingwith saidshoulders to limit the dewnward movement of the cutters,

L0. jA-n underreamer comprising a body having slideways, cutters having, shanks slidable. therein and provided with stop. shoulders adjacent their upper ends, means fOh/tran'slating the cutters, in combination with a transverse key locatedto one side of the, translating means, carried by the body, cooperating with said shoulders to limit the downward movement of; the cutters and re- ,movable to ,permit a withdrawal of the out ters-fromthe body.

11;, An underrean er com-pris ng body having a sprmg chamber and a central bore extending downwardly therefrom, a rod slidablewithin said bore and extending into the spring chamber, cutters supported-upon thero'd, a spring within said chamber sun rounding the rod, and a nut screw threaded on the upper end of; the rod with its side I said body, means removably carried by the body located to one. side of said translating means, and cooperating with 1 said step shoulders to. maintain the cutters within the body if a disabling of said translating IHBfLIlSOCCllI'S.

13. An underreamer comprising a body having slideways, cutters slidable therein and transversely expandable, a spring actuated rod for operating the cutters having "a fixed head with cutter supporting table surfaces on opposite sides of the rod shank extending across the shank in the direction of, cutter expansion, and a nut mounted in the body and receiving the upper endof said spring rod to facilitate adjustment of the same.

14a. lAn underreamer body having opposed slots upwardly from its lower end defining 'an intermediate web providing cutter latching and expanding hon. r o ni ial y 9. An underreamer comprising a body. having slideways, cutters slidable' therein expanding the cutters, and projections eX- tending from the lower end of the body on opposite sides of the slots and providing inthrust bearing surfaces for completingthe expandingof the cutters.

15. .An underreamer body having opposed slots upwardly from its lower edge defining an intermediate web and a chamber above SZtlCi;\V6b, the walls of said chamber being apertured to receive a cutter retaining key.

16. An underreamer body having opposed slots upwardly from its lower edge defining an lntermedlate web providing cutter latch,-

ing and expanding shoulders, the side walls of the slots being grooved to form cutter slideways having outthrustbearing surfaces, projections extending downwardly from the lower end'of the body between the slots .de fining upthrust bearing surfaces on opposite sides of each projection and providing. an gled inthrust bearing surfaces. r

17. An underreamer cutter having a shank Jdefining an upthrust bearing surface on each side of the shank, ribs on the sides of. the

shank defining outthrust bearing surfaces, and a transverse groove in the upper portion of the shank defining a stop shoulder.

18. An underreainer cutter having a shank defining an upthrust bearing surface on each side of the shank and r bs on the sldes of the,

shank defining outthrust bearing surfaces, a projection on the inner wall of the shank providing an expanding cam shoulder, and projections and adjacent recesses on the in ner wall oftheyc utter body on opposite sides of the shank adapted tointermesh with those of a companioncutter.

19. An underreamer; cutter having abodyv portion and a shank defining upthrustbefaring surfaces on the bodyon opposite sides. of the shank, ribs on; opposite sides of the" shank defining outthrustbearing surfaces,,a

projection on" the inner wallgof the shank:

defining an expanding cam shoulden ga, pocket 1n the inner wall, of the, cutter body.

defining cutter supporting ledges, and pro: ections and ad acent rQGQSSes-on-,each. side.

of said pocket adapted to. intermesh with those of a companion cutter, with the.proections forming angled inthrust bearing surfaces.

20. In an underreame t; the combination of a ody, a pa r i xpans lec tter nted on the body, spring actuated meanscoop crating withthe cutters and supported the body, said; body permitting a longitudinal movement of the: cutters, on thebody, and. having faces ITGOQLVHIQ, the inthrust of ;the er henthe ame-t r ntheincom l t ly;

expanded position, and operating by an up ward movement of; said body when the cuttersarestuck 1n the hole, 20 Wi hdraw said supporting faces. and. permit? an inward; movement of the cutters, thereby effecting.

he re ease. in t hole :21. In an underreamer, the combination of a body, a pair of expansible cutters mounted on the body, spring actuated means cooperating with the cutters and supported in the body, said body permitting a longitudinal movement of the cutters on the body, said body having inclined supporting faces receiving the inthrust of the cutters when the same are in their completely expanded position, and operating by an upward movement of said body when the cutters are stuck in the hole, to withdraw said supporting faces and permit an inward movement of the cutters, thereby effecting their release in the hole.

22. In an underreainer, the combination of a body, a pair of expansible cutters mounted to move longitudinally in the body, means for rigidly supporting the inthrust of the cutters when completely expanded, and means for effecting a slight contraction of the cutters rendered operative by an upward movement of the body when the cutters are stuck and held fixed by the wall of the hole.

23. In an underreamer, the combination of a body, a pair of cutters mounted on opposite sides of the body and capable of 1ongitudinal movement on the body, said cutters having shanks at their upper ends, each of said shanks having a groove on its side with an elevated shoulder, a transverse key in the body cooperating with the shoulders to limit the downward movement of the cutters, spring actuated means cooperating with the cutters for pulling the same upwardly on the body, said cutters and said body having means cooperating to efiect the expansion and collapsing of the cutters by a downward movement of the body and an upward movement of the body with respect to the cutters.

9A. In an underreamer, the combination of a body, a pair of oppositely disposed cutters having shanks extending upwardly in the body, each of said shanks having a groove on its side face with an elevated shoulder, a transverse key in the body cooperating with the shoulders to limit the downward movement of the cutters, spring actuated means for pulling the cutters upwardly in the body, said body and said cutters having means cooperating to effect a slight inward movement of the cutters initiated by an upward movement of the body when the cutters are stuck and fixed in the hole, thereby effecting the release of the cut-- ters.

25. In an underreamer, the combination of a body, a pair of expansible cutters supported thereby, the inner side of each cutter having a projection cooperating with the body in expanding and collapsing movement of the cutters, each cutter also having a recess on its inner side, the said recesses and projections being located so that when the cutters are collapsed the projection in one cutter is received in the recess of the other cutter.

Signed at Los Angeles, California, this 1st day of August, 1921.

WILLIAM YOULE.

Witnesses:

CLARENCE B. Fos'rnn, L. BELLE WEAVER. 

